Merge branch 'merge-base-pipeline' into 'master'

Introduce MergeRequest#merge_base_pipeline for CodeQuality artifact comparison to merged results

See merge request gitlab-org/gitlab!44648

app/models/merge_request.rb

@@ -1599,6 +1599,12 @@ class MergeRequest < ApplicationRecord
       .find_by(sha: diff_base_sha, ref: target_branch)
   end
 
+  def merge_base_pipeline
+    @merge_base_pipeline ||= project.ci_pipelines
+      .order(id: :desc)
+      .find_by(sha: actual_head_pipeline.target_sha, ref: target_branch)
+  end
+
   def discussions_rendered_on_frontend?
     true
   end

app/serializers/merge_request_widget_entity.rb

@@ -120,9 +120,13 @@ class MergeRequestWidgetEntity < Grape::Entity
     end
 
     expose :base_path do |merge_request|
+      if use_merge_base_with_merged_results?
+        merge_base_pipeline_downloadable_path_for_report_type(:codequality)
+      else
         base_pipeline_downloadable_path_for_report_type(:codequality)
       end
     end
+  end
 
   expose :security_reports_docs_path do |merge_request|
     help_page_path('user/application_security/sast/index.md', anchor: 'reports-json-format')
@@ -156,6 +160,16 @@ class MergeRequestWidgetEntity < Grape::Entity
     object.base_pipeline&.present(current_user: current_user)
       &.downloadable_path_for_report_type(file_type)
   end
+
+  def use_merge_base_with_merged_results?
+    Feature.enabled?(:merge_base_pipelines, object.target_project) &&
+      object.actual_head_pipeline&.merge_request_event_type == :merged_result
+  end
+
+  def merge_base_pipeline_downloadable_path_for_report_type(file_type)
+    object.merge_base_pipeline&.present(current_user: current_user)
+      &.downloadable_path_for_report_type(file_type)
+  end
 end
 
 MergeRequestWidgetEntity.prepend_if_ee('EE::MergeRequestWidgetEntity')

config/feature_flags/development/merge_base_pipelines.yml

+---
+name: merge_base_pipelines
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/44648
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/263724
+type: development
+group: group::testing
+default_enabled: false

spec/models/merge_request_spec.rb

@@ -3520,6 +3520,25 @@ RSpec.describe MergeRequest, factory_default: :keep do
     end
   end
 
+  describe '#merge_base_pipeline' do
+    let(:merge_request) do
+      create(:merge_request, :with_merge_request_pipeline)
+    end
+
+    let(:merge_base_pipeline) do
+      create(:ci_pipeline, ref: merge_request.target_branch, sha: merge_request.target_branch_sha)
+    end
+
+    before do
+      merge_base_pipeline
+      merge_request.update_head_pipeline
+    end
+
+    it 'returns a pipeline pointing to a commit on the target ref' do
+      expect(merge_request.merge_base_pipeline).to eq(merge_base_pipeline)
+    end
+  end
+
   describe '#has_commits?' do
     it 'returns true when merge request diff has commits' do
       allow(subject.merge_request_diff).to receive(:commits_count)

spec/serializers/merge_request_widget_entity_spec.rb

@@ -88,25 +88,53 @@ RSpec.describe MergeRequestWidgetEntity do
   end
 
   describe 'codequality report artifacts', :request_store do
+    let(:merge_base_pipeline) { create(:ci_pipeline, :with_codequality_report, project: project) }
+
     before do
       project.add_developer(user)
 
       allow(resource).to receive_messages(
+        merge_base_pipeline: merge_base_pipeline,
         base_pipeline: pipeline,
         head_pipeline: pipeline
       )
     end
 
-    context "with report artifacts" do
+    context 'with report artifacts' do
       let(:pipeline) { create(:ci_pipeline, :with_codequality_report, project: project) }
+      let(:generic_job_id) { pipeline.builds.first.id }
+      let(:merge_base_job_id) { merge_base_pipeline.builds.first.id }
+
+      it 'has head_path and base_path entries' do
+        expect(subject[:codeclimate][:head_path]).to be_present
+        expect(subject[:codeclimate][:base_path]).to be_present
+      end
+
+      context 'on pipelines for merged results' do
+        let(:pipeline) { create(:ci_pipeline, :merged_result_pipeline, :with_codequality_report, project: project) }
+
+        context 'with merge_base_pipelines enabled' do
+          it 'returns URLs from the head_pipeline and merge_base_pipeline' do
+            expect(subject[:codeclimate][:head_path]).to include("/jobs/#{generic_job_id}/artifacts/download?file_type=codequality")
+            expect(subject[:codeclimate][:base_path]).to include("/jobs/#{merge_base_job_id}/artifacts/download?file_type=codequality")
+          end
+        end
+
+        context 'with merge_base_pipelines disabled' do
+          before do
+            stub_feature_flags(merge_base_pipelines: false)
+          end
 
-      it "has data entry" do
-        expect(subject).to include(:codeclimate)
+          it 'returns URLs from the head_pipeline and base_pipeline' do
+            expect(subject[:codeclimate][:head_path]).to include("/jobs/#{generic_job_id}/artifacts/download?file_type=codequality")
+            expect(subject[:codeclimate][:base_path]).to include("/jobs/#{generic_job_id}/artifacts/download?file_type=codequality")
+          end
+        end
       end
     end
 
-    context "without artifacts" do
-      it "does not have data entry" do
+    context 'without artifacts' do
+      it 'does not have data entry' do
         expect(subject).not_to include(:codeclimate)
       end
     end